Create a Kalatheme sub-theme project right on Pantheon
Pull it down to your laptop on Kalabox
Work on it in Eclipse IDE, for example
What flavor is Kalatheme?
Kalatheme is a very convenient theme to use, and should be the default theme for Panopoly, with all due respect. Peruse its Drupal project page. Panopoly + Bootstrap 3 + Bootstrap themes + browser based sub-theme generator (<- Bootswatch, etc., etc.!) + views grids + reusable custom CSS classes that can be registered as optional in any panels pane + advanced stuff for the folks that, inline with Kalatheme philosophy, don’t like to admit they use it:Sass and Compass Tools.